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/**
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* \file pcm/pcm_empty.c
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* \ingroup PCM_Plugins
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* \brief PCM Null Plugin Interface
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* \author Jaroslav Kysela <perex@perex.cz>
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* \date 2006
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*/
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/*
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* PCM - Null plugin
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* Copyright (c) 2006 by Jaroslav Kysela <perex@perex.cz>
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*
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation; either version 2.1 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#include "pcm_local.h"
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#include "pcm_plugin.h"
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#ifndef PIC
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/* entry for static linking */
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const char *_snd_module_pcm_empty = "";
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#endif
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/*! \page pcm_plugins
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\section pcm_plugins_null Plugin: Null
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This plugin discards contents of a PCM stream or creates a stream with zero
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samples.
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Note: This implementation uses devices /dev/null (playback, must be writable)
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and /dev/full (capture, must be readable).
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\code
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pcm.name {
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type null # Null PCM
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}
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\endcode
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\subsection pcm_plugins_null_funcref Function reference
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_snd_pcm_empty_open()
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*/
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/**
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* \brief Creates a new Empty PCM
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* \param pcmp Returns created PCM handle
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* \param name Name of PCM
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* \param root Root configuration node
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* \param conf Configuration node with empty PCM description
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* \param stream Stream type
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* \param mode Stream mode
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* \retval zero on success otherwise a negative error code
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* \warning Using of this function might be dangerous in the sense
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* of compatibility reasons. The prototype might be freely
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* changed in future.
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*/
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int _snd_pcm_empty_open(snd_pcm_t **pcmp, const char *name ATTRIBUTE_UNUSED,
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snd_config_t *root, snd_config_t *conf,
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snd_pcm_stream_t stream, int mode)
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{
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snd_config_t *slave = NULL, *sconf;
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snd_config_iterator_t i, next;
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int err;
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snd_config_for_each(i, next, conf) {
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snd_config_t *n = snd_config_iterator_entry(i);
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const char *id;
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if (snd_config_get_id(n, &id) < 0)
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continue;
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if (snd_pcm_conf_generic_id(id))
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continue;
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if (strcmp(id, "slave") == 0) {
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slave = n;
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continue;
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}
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SNDERR("Unknown field %s", id);
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return -EINVAL;
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}
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if (!slave) {
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SNDERR("slave is not defined");
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return -EINVAL;
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}
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err = snd_pcm_slave_conf(root, slave, &sconf, 0);
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if (err < 0)
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return err;
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err = snd_pcm_open_named_slave(pcmp, name, root, sconf, stream,
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mode, conf);
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snd_config_delete(sconf);
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return err;
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}
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#ifndef DOC_HIDDEN
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SND_DLSYM_BUILD_VERSION(_snd_pcm_empty_open, SND_PCM_DLSYM_VERSION);
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#endif
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